Circuit breaker



CIRCUIT BREAKER Filed Nov. 4, 1942 2 Sheets-Sheet l M. G. LEONARD oFF i Aug.r 29, 1944.

mvENToR Merril! Gileamad. v U q1?? I I ATro EY iilli uvwazI-n: 1

Aug. 29, 1944. *M G, LEONARD 2,357,210

CIRCUIT BREAKER Filed Nov. 4, 142 2 sheets-sheetv 2 F237. 4. Hy. 7

Merrill G. Leonard.

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Patented Aug. k29, 1944 CIRCUIT BBEAKEB,

Merrill G. Leonard, Sharon, Pa., assignor to Westinghouse Electric Manufacturing Company, g East Pittsburgh, Pa., a corporation of Pennsylvania Appucauonmv'enber 4, 1942, seria1No.464,441

(c1. zoo- 116) 20 Claims.

This invention relates tocircuit breakers'and more particularly to circuit breakers oi' the type which are tripped open automatically on overloads and which may be manually operated to open and closed positions.

An object of the invention is the provision of a circuit breaker having an improved operating mechanism wherein an actuating member engages a toggle to operate the toggle to open and closed positions, the togglel moving free of the actuating member in response to overload currents.

Another obj ect of the invention is toprovide an improved operating mechanism for a circuit breaker comprising a pivoted actuating member -normally engaging a toggle to operate said toggle to open and to close the contacts, the toggle being operable to automatically open'the contacts without displacing the actuating member.

Another object of the invention is to provide an improved operating mechanism for a circuit breaker wherein the force of the overcenter operating spring is applied to an actuating member which is operable to cause opening and closing oi' the contacts without applying the force o! the overcenter spring to the latch mechanism of the breaker.

Another object of the invention is to provide a circuit breaker with an improved operating mechanism having an operating handle and a snap action overcenter spring that is connected to an intermedi-ate lever to which the contact mechanism is releasably connected in such a manner that the snap action spring does not add to the latch load oi the breaker. n

Another object of the invention is to provide a circuit breaker with an improved operating mechanism operable to produce quickl make and break oi the contacts and automatic opening of the contacts trip free oi' the handle and wherein only a relatively small amount of energy is required to reset the mechanism.

Another object o! the invention is to provide a circuit breaker with an improved operating mechanism that is manually and automatically operable to open and reclose the contacts.

Another object of the invention is the provision o! an improved operating mechanism wherein the operating toggle is operated by an actuating member to open and close the contacts, the actuating member being operated by an overcenter spring in a manner to permit automatic operation oi' the toggle and automatic resetting of the trip device.

Another object of the invention is the provision of an improved operating mechanism for a circuit breaker which is simple, accurate and reliable in operation and inexpensive to manufacture.

The novel features that are considered charac- .teristic of the invention are set forth in particubreaker embodying the principles of the invention, the breaker being shown in the closed circuit position;

Fig. 2 is a fragmentary view of the circuit breaker showing the circuit breaker mechanism in the tripped open position;

Fig. 3l is a fragmentary view of the circuit breaker showing the circuit breaker mechanism in the open or reset position;

Fig. 4 is a fragmentary view of a circuit breaker embodying a modication of the invention and showing the circuit breaker mechanismr in the closed position;

- Fig. 5 isa detail view of the actuator of the embodiment shown in Figs. 1 to 3;

Fig. 6 is a detail view of the actuator of the modication shown in Fig. 4;

Fig. 'I is a fragmentary view of a circuit break- I er embodying the modification shown in Fig. 4 and showing the breaker in the tripped open position but with the circuit breaker mechanism in the automatically reset position.

Fig. 8 is a fragmentary view of a circuit breaker having a mechanism .similar to that ot Fig. 4 and also embodying an automatic reclosing means; and

Fig. 9 is a vertical' sectional view through the circuit breaker shown in Fig. 1 and taken sub- Referring to Fig. 1 of the drawings. the circuit breaker comprises a baseil and a cover I3 both of insulating material, a stationary contact I5 and a cooperating movable contact. I1, an operating mechanism indicated generally at I! and a trip device 2|.V

The stationary contact Itis secured to a conductor 23 having a terminal connector 25. The movable contact I1 is attached to the free end of a resilient contact arm 21 which is secured to a channel-shaped arm 29. The arm 29 is pivotally mounted on a pivot pin 3i supported in a U- shaped main frame 33 secured by means of screws 35 to the base 'I'he resilient contact arm 21 is connected by means of a ilexible shunt conductor 31 to the free end of a bimetal element 39 comprising the trip device. The bimetal element 39 is secured to a conductor 4| and to the base by screws 43. The conductor extends out of the breaker housing and forms a terminal connector 45. The circuit of the breaker extends from the terminal 23 through the conductor 23, stationary and movable contacts i--|1, contact arm 21, flexible shunt conductor 31, the bimetal element 39, and the conductor 4| to the terminal 45.

The operating mechanism i9 includes a carrier lever 41 pivotally mounted on a pivot pin 49 supported in the main frameK -33 and biased in a clockwise direction by a spring 34 coiled about the pivot pin 49. One end of the spring 34 is hooked over a stop member 33 formed inwardly from the frame 33 and the other end engages the carrier lever 41. The carrier 41 is provided with a latching end 5| which normally engages a latch 53 secured on the bimetal element 39 near the free end thereof and insulated therefrom. The carrier is operatively connected to the channel arm 29 by means of a toggle comprising toggle links 55 and 51 pivotally connected by means of a knee pivot pin 53. The toggle link 55 is pivotally connected by means of a pivot pin 6| to the carrier 41 and the toggle link 51 is pivotally connected to the channel member-29 by means of a pivot pin 33.

In the closed position of the parts the toggle 55-51 is overcenter to the right of a line through the pins 9|-63 and in this position, with the carrier 41 latched up, the toggle holds the contact arm 29-21 in closed position against the bias of a spring 35. The spring 35 has one end anchored in the side of the channel member 29 and the other end hooked over a spring stud 31 supported in the frame 33. The spring 65 at all times biases the contact arm 21-29 in opening direction.

Also forming a part of the operating mechanism is a U-shaped operating lever 33 whose legs 10 (Fig. 9) straddle the frame 33 and are pivotally mounted on pivot pins 1| supported on the opposite sides of the frame 33. Mounted on the outer portion of the operating lever 59 is an operating handle 13 of insulating material which projects outwardly through an opening 15 in the cover |3. A shield 11 also of insulating material and molded integral with the handle 13 serves to cover the opening 15. An actuator comprising a pair oi actuating arms or lever arms 19 (Fig. 5) is pivotally mounted on fixed pivots 3| (see Figs. 2 and 9) supported in the sides of the frame 33. In the closed position of the breaker the pivot pin 3| which connects the toggle link 55 to the carrier 41 is in axial alignment with the pivot pins 3i for the actuating arms 13 of the actuator.

With the handle 13 in the on position (Fig. l) the actuator 19 is biased by means of overcenter springs 93, against stops 85 (Figs. 3 and 9) projecting inwardly from the sides of the frame 33. The overcenter springs 33 have their outer ends anchored to the outer portion of the operating lever 39 and their inner ends are attached to the adjacent arms 19 (Fig. 9) of the actuator by means of spring studs 31. The springs 33 also bias the operating lever against a stop 33 formed outwardly from the frame 33.

The free end of the `actuator arms 19 are formed into hooks 39 which, in the closed posiassaggio tion of the breaker, embrace the knee pin 33 o! the toggle 55-51 as shown in Figures 1, 3, 5 and 9.

Upon the occurrence o! an overload current in the circuit of the breaker the bimetal 33, when heated a predetermined amount thereby will denect in a direction to release the carrier 41. As soon as the carrier is released, the spring 33 acts to rotate the contact arm 21-29 counterclockwise to open the contacts. As the contact arm rotates, the toggle 53-31 moves upwardly in substantially a straight line without breaking overcenter, and, assisted by the spring 34, rotates the carrier 41 clockwise about its pivot 43, the clockwise movement of the carrier being limited by engagement thereof with the stop member 33. The first part of the upward movement of the toggle carries the knee pin 59 out oi' the hooks 33 on the actuating arms 13. As the movement continues, a projection 3| on the carrier 41, which is moving in a clockwise direction, engages the knee pin 69 and'moves theftoggle 35-51 overcenter to the left of the line Iii-33. In this position (Fig. 2) the contacts are fully open and the contact arm 21-29 is biased against a stop 93 on the frame 33 and the carrier 41 is biased against the stop 33.

Before the contacts may be closed following an automatic opening operation, it is necessary t0 first relatch the carrier 41 with the trip device. This is accomplished by manually rotating the operating lever 69 counterclockwise from the "on position (Fig. 2), in which it remained during the automatic opening operation, to the oil position (Fig. 3). During this movement of the lever 69, the line of action of the springs 33 pass overcenter to the left of the pivot axis 3| of the actuator 19 whereupon the actuator is rotated clockwise to its Fig. 3 position with a snap action, the arms 19 of the actuator being arrested by engagement with the knee pin 59. Shortly after this occurs a projection 91 on the operating lever -69 engages the carrier 41 and continued movement of the operating lever in resetting direction rotates the carrier in a counterclockwise direction to its latched position (Fig. 3). As the carrier moves to latched or reset position, the toggle 55-51 is moved farther in collapsed direction thrusting the knee pin 33 into the hooks 33 on the actuating arms 19.

The contacts can now be closed by moving the lever 39 clockwise from the "oil" position (Fig. 3) to the on" position (Fig. 1). During this movement of the operating lever, the springs 33 pass to the right of the pivot axis 3| for the actuator 19 whereupon the springs 33 bias the actuator in a counterclockwise direction, and, since the knee pin 59 of the toggle 55-51 is now engaged with the hook 39, the toggle is biased to its overcenter position. Continued clockwise movement of the operating lever 39 increases the spring bias on the toggle until a point is reached when the bias oi' the springs 33 overcomes the tension of the weaker contact spring 33 and moves the actuator 19 and thereby moves the toggle 33-31 over center to its Fig. 1 position to close the contacts with a snap action.

The breaker is manually operated to the open position by moving' the handle 13 counterclockwise from the on" position (Fig. 1) to the oil position (Fig. 3). During this movement of the handle the line of action of the overcenter springs 33 passes to the left oi' the pivot axis 3| of the actuator 13, and biases the actuator in a clockwise direction. C o n tin u e d counterclockwise ciockwisewithasnapaction. lachoithearmamovement o! the' handle increases the biasing force-until a point is reached when the springs Il yrotate' the actuator 19 clockwise about the pivot axis The actuator 19 carries the knee of the toggle "-01 therewith, and, as soon as the toggle has moved overcenter, the springs Il assisted by the contact spring 00 complete the movement and open the contacts with a snapv action. During the manual opening vmovement the actuator 19 and the upper toggle link 55 move as a unit, since their respective pivots are in axial alignment, and the kneey pin 59 remains in engagement with'the hooks 99 of the actuator.

The contacts can be closed, following a manual opening operation, in the previously described manner by moving the handle 19 to the on position.

According to the modification of the invention shown in Figs. 4 and '1, the carrier l1 is automatically reset to latched position as soon as the contacts have opened. Since the mechanism shown iny Fig. 4 is substantially the same as that shown in Figs. l, 2 and 3, like reference characters have been given to like parts.

Referring to Fig. 4, the spring 34 (Fig. 1) which biases the carrier in a clockwise direction is omitted and the carrier l1 is biased to reset position by a relatively weak spring 99 tensioned between the spring stud 91fon the frame 39 and a spring stud |0| on the carrier. is substantially weaker than the contact opening spring 05 and therefore does not materially retard opening movement of the contacts Upon release of the carrier 41, in response to an overload current, the spring 0I rotates the contact l arm 21-29 counterclockwise thrusting the toggle 55--51 upwardly and rotating the carrier 41 clockwise. This moves the knee pin 59 out oi' the hooked end of the actuator 19a and at this time the projection 9| on the carrier 41 engages the knee pin 59 and moves the toggle 55-51 overcenter to cause its collapse. When the contact arm 21--29 reaches its fully open position (Fig. 2) against the stop 93 the spring I6 no longer biasesthe carrier. As soon as the toggle 05-51 collapses the spring 99 reacts toreset the carrier 41 counterclockwise from its operated position to its relatched position,v the counterclockwise movement of the carrier being limited by a stop |00 projecting inwardly from the frame 33. At this time, the carrier 41, the toggle 55-51 and the contact arm 21-29 are in the position shown in Fig. 3 but the operating lever 89 and the actuator 19a are in the position shown in Fig. 4.

In order to close the contacts, it is first necessary to move the operating lever 69 counterclockwise from its Fig.-4 position to the ofi position in order to reengage the actuator 19a with the knee pin 59 of the toggle. Ii the arm 19 (Fig. 5) were used in the Fig. 4 modification, the hooks I9 would strike the knee pin 59 but would fail to properly engage the knee pin since the carrier 41 has already been automatically resetl and the knee pin B9 moved to its Fig. 4 position, In order to ensure the proper engagement of the actuator 19a with the knee pin, the modified actuator comprising a pair of actuating arms 19a shown in detailin Fig. 6 is provided. With the carrier 41 and the toggle 55-51 in the reset position such as shown in Fig. 3, the operating 1ever 69 is' rotated counterclockwise to its oil position. During this movement the springs 09 pass overcenter to the left of the pivot 8| of the actuator 19a, causing this member to rotate The spring 99 of the actuator 19a (Fig. 0) is provided with an elongated slot |00 through which the pivot pin 0| passes, and a cam face Ill for engaging the knee pin I9. When, during the clockwise moveyment of they actuator 19a', the cam face Ill strikes the knee pin 59, the actuator 19a is moved bodily downwardly until the hook passes the knee pin whereupon the springs 0I move the arms 19a upwardly engaging the hook with the knee pin. The operating lever 09 is then manually rotated to its on" position and the springs Il, as they pass overcenter to the right of the pivot axis Il, cause counterclockwise rotation of the actuator 19a to straighten the toggle and close the contacts with a snap action inthe previously described manner.

yFigure 8 illustrates a further modification of the invention embodying van automatic reclosing means. This means comprises, a solenoid |01 suitably mounted on but insulated from a projection |09 of the frame 33 oi the automatic resetting breaker shown in Figs. 4 and '1. The solenoid |01 comprises a winding (not shown)- and a movable core member I Il which at its right hand end (Fig. 8) carries a cross member ||l adapted to engage the toggle 05-51 at or near its knee. The winding of the solenoid |01 may be connected in a control circuit (not shown) and energized from any suitable source under the control of a manually or automatically operable switch (not shown).

After the breaker has been tripped open by oneration of the trip device 2| in response to an overload current and after the carrier "has been automatically reset to latched position, the energizing winding'of the solenoid |01 is ener-` gized operating the movable core member lil toward the right (Fig. 8). During this movement the member H5 on the end of the core. member H3 engages the knee of the toggle lB-Il antil ,wa-s tripped open, the outer end of the toggle is held against opening movement and the action of Ithe solenoid t0 straighten the toggle 05-51 results in rotating the movable switch member 21,--29 in a clockwise direction to close the Icontacts.

As the toggle -51 approaches its overcenter position during the closing movement. the knee pin 59 engages the surfaces |05 (see also Fig. 6) and cause the actuator 19a downwardly in order to reengage the hooked ends thereof with the knee pin.

It will be obvious that the circuit breaker shown in Fig. 8 may be manually operated to open and to close the contacts in the manner previously described for manual operation of the Figure 4 modification. Except for the closing solenoid the structure and parts of the breaker shown in Fig. 8 are the same asthe corresponding parts of the Fig. 4 embodiment 'and have been indicated by the same reference characters. v

In conventional circuit breakers of the general type disclosed herein, the overcenter operating springs are usually connected directly to the knee of the toggle and through the toggle and the carrier apply the heavy spring load to the latch, thus creating an undesirably heavy lach load.

'It will, therefore. be seen that by the present inprovision of the substantially weaker contact operating spring E5. In accordance with the modification of the invention there has been provided a simple automatic resetting means for the mechanism which permits the use of a very simple automatic reclosing means.

It will be noted that the operating handle does not move from the on" position when the breaker is automatically operated to the open position. Thisvieature of the invention is an advantage in certain applications of the breaker. With the present invention the extent of travel of the handle is not critical. This is an advantage over many prior art breakers since in many conventional breaker mechanisms, if the closing movement of the handle is restricted too much the contacts may not close, and if the handle overtra'vels slightly the toggle may lock in and the contacts fail to open. Another advantage of the present invention isl that because of the small amount of stretching of the overcenter springs 1nvolved during resetting less energy is required to reset the mechanism by manual or automatic control than is required by many conventional breakers when the overcenter springs must be stretched a considerable amount in resetting the breaker.

Having described preferred embodiments of the invention in accordance with the Patent Statutes, it is to be understood that various changes and modications may be made in the structural details thereof without departing from some of the essential features of the invention. It is desired, therefore, that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

I claim as my invention:

l.' A circuit breaker comprising relatively movable contacts, operating mechanism for said contacts including a toggle operatively related to said contacts, an actuating member separably engaging said toggle, said actuating member being operable to operate the vtoggle to open and close the contacts, current responsive means operable to eii'ect opening movement of said toggle and contacts irrespective of the position of said actuating member, and means for resetting said mechanism and for eiecting reengagement of said actuating member with the toggle.

2. A circuit breaker comprising relatively movable contacts, operating mechanism for said contacts including a toggle operable to permit opening of said contacts, an actuating member separably engaging said toggle and operable to operate the toggle to open and close the contacts with a snap action, an element operable ln response to overload currents to eiect opening operation of said toggle and contacts irrespective of the position of said actuating member, and an overcenter spring for operating said actuating member to reengage said actuating member with the toggle and for operating said toggle to close the contacts with a snap action.

3. A circuit breaker comprising relatively movable contacts, operating mechanism for said contacts including an operating handle, an actuating member, an overcenter spring operable by said handle to operate the actuating member, a toggle normally engaging the actuating member and operable thereby to open and close the contacts with a snap action, and means operable upon the occurrence of predetermined conditions to eiect opening operation of said toggle and contacts irrespective of the position of said handle and said actuating member, said toggle disengaging the actuating member upon automatic operation of said toggle.

4. A circuit breaker comprising relatively movable contacts, a switch member operable to open and close said contacts, means for releasably restraining the switch member in closed position, means connecting said switch member to said restraining means and operable upon release of said restraining means to permit opening movement of said switch member, an actuating member separably engageable with the connecting means for moving said switch member to closed position, operating means for said actuating member including an overcenter spring for operating said actuating member to close the contacts with a snap action.

5. A circuit breaker comprising relatively movable contacts, operating mechanism for said contacts including a toggle for restraining said contacts in closed position and operable to elect opening of said contacts, an actuating member normally engaging said toggle, means including an overcenter spring for operating said actuating member to open and closed positions to edect opening and closing of the contacts, current responsive means for eiecting opening operation of said toggle and contacts irrespective oi the position of said actuating member, said toggle being disengaged from said actuating member upon automatic opening movement of said toggle, and said overcenter spring being operable to effect reengagement of the actuating member and toggle.

6. A circuit breaker comprising relatively movable contacts, a switch member movable to open and close said contacts, operating mechanism for said switch member including an operating lever, a releasable member, a toggle connecting said releasable member to said switch member, said toggle being operable upon release of said releasable member to eiiect opening movement of the switch member, an actuating member separably engageable with said toggle for operating said toggle to close the contacts, and an overcenter spring operable by said operating lever for operating said actuating member.

7. A circuit breaker comprising separable contacts, a switch member movable to open and close said contacts, operating mechanism for said switch member including an operating handle operable to eilect opening and closing of said contacts, a releasable member for releasably restraining said switch member in closed position. atoggle operatively connecting said releasable member to said switch member, an actuating member normally engaging said toggle, said toggle being separable from said actuating member upon release of said releasable member to open the contacts, and an overcenter spring operable by said operating handle to reengage said actuating member with said toggle.

8. A circuit breaker comprising relatively movable contacts, a switch member movable to open and closed positions to open and close said contacts, operating mechanism for said switch member including an actuating member, an overcenter spring for operating said actuating member, a member releasably restraining said switch member in closed position and operable to efiect movement of said switch member to open position, a toggle connecting said switch member to said releasable member, said toggle being normally engaged with said actuating member, current responsive means for releasing said releasable member to eil'ect opening movement of said assaaio switchmembeasaid toggledisengagingtheactuating member during opening movement oi said switch member, and means for operating said overcenter spring to elect r'eengagement oi said actuating member with said toggle and for operating said toggle to eiiect movement ci the switch vmember to closed position.

9. A circuit breaker comprising relatively movable contacts, operating mechanism i'or said contacts including a toggle, a pivoted actuating actuating member normally engaging said toggle.

member separably engaging said toggle ior operating the toggle to open and close said contacts, means including an overcenter spring for operating said actuating member, a bimetal element operable when heated in rponseto overload currents to eiTect operation oi said toggle to open said contacts irrespective oi.' the position oi said actuating member, said actuating member being operable to reengage the toggle.

10. A circuit breaker comprising relatively movable contacts, operating mechanism ior said contacts including a toggle operable to open and close said contacts, an actuating member cooperating with said toggle and operable to open and-closed positions for operating said toggle, means including an overcenter spring for operating said actuating member, a trip device including an element operable when energized a predetermined amount to eil'ect an opening operation of said toggle irrespective oi the position of said actuating member, and means for automatically resetting said trip device following an automatic opening operation.

11. A circuit breaker comprising relatively movable contacts, operating mechanism for said contacts including a toggle operable to open and close said contacts, an actuator separably engageable with said toggle for operating said toggle to open and close the contacts, means including an overcenter spring for operating said actuator to open and closed positions with a snap action, a trip device operable in response to overload currents for eiecting operation of the toggle to open position irrespective of the position of said actuator, means for automatically resetting said trip device following an automatic operation ofthe breaker, said actuator being operable to reengage the toggle after said trip device is reset.

12. In a circuit breaker thecombination oi' relatively movable contacts, operating mechanism therefor including a link operatively related to said contacts, an actuating member releasably engaging said link and operable to open and close the contacts with a snap action, cur,

rent responsive means operable in response to overload currents to cause release of said link from said actuating member and opening operation oi said link and the contacts irrespective oi' the position of the actuating member, and an overcenter spring for operating the actuatlng member.

13. In a circuit breaker the combination of relatively movable contacts, operating mecha nism for said contacts including a member rean operating handle for operating said actuating member to lopen -and closed positions to eilect opening and closing of the contacts, cur- `rent responsive means i'orA eilecting automatic opening operation of said toggle and said con-A tacts irrespective oi' the position of said actuating member, said toggle being disengaged from said actuatingy member upon automatic opening movement of said toggle, and said handle being operable to eiIect reengagement oi' the actuating member and the toggle.

15. In a circuit breaker the combination oi relatively movable contacts, operating mechanism for said contacts including an operating lever, releasable means including a member operable upon release of said releasable means to effect opening' of said contacts, an actuating member separably engageable with said releasable member for operating said releasable member to close the contacts, and an overcenter spring operable by said operating lever for operating said actuating member.

16. In a circuit breaker,the combination of relatively movable contacts, operating mechanism for said contacts including an operating handle, a-releasable member, a toggle operatively associated with said releasable member and said contacts and operable upon release of said releasable member to eiIect opening of said contacts, an actuating member normally engaging said toggle, said toggle being separable from said actuating member upon release of said releasable member, and said handle being operable to reset said releasable member and to reengage the actuating member with the toggle.

17. In a circuit breaker, the combination of relatively movable contacts, operating mechanism for said contacts handle, a releasable member, a toggleoperatively associated with said releasable member and the movable contact and operable upon release of said releasable member to enect opening of the contacts, an actuating member normally engaging said toggle, said from said actuating member upon release of the releasable member, and means for automatically resetting said releasable member following an automatic opening operation, said handle being operable to eiect reengagemerit of the actuating member and the toggle.

18. In a circuit breaker, the combination of relatively movable contacts, operating mechanism for said contacts including an operating handle, a releasable member, a toggle operatively associated with said releasable member and said contacts, said toggle being operable upon release of said releasable member to eilect opening of the contacts, an actuator normally engaging said toggle, said toggle being separable ,from said actuator upon release of the releasable member, means for automatically resetting said releasable member following an automatic opening operation, said handle being operable to effct reengagement of the actuator and said togg e, and electroresponsive means for operatin said toggle to reclose said contacts. g

including an operating toggle being separable 19. In a circuit breaker, the combination of relatively movable contacts, operating mechanism for said contacts including a releasable member, a toggle operatively associated with said releasa'ole member and said contacts, said member when released causing opening of said contacts, an actuating member operable to move said toggle to open and close the contacts, current responsive means operable in response to overload currents to release said releasable member and eiect operation or said toggle irrespective of the position of said actuating member, means for automatically resetting said releasable member following an automatic opening operation, and electroresponsive means etigageable with the toggle for operating said toggle to close the contacts.

20. A'circuit breaker having relatively movable contacts, operating mechanism therefor comprising a support member releasable to cause automatic opening of said contacts, a member movably supported on said support member and connected to the movable contact, an actuating element disengageably related with said movable member for moving said movable member to open and close' the contacts, an operating handle and an overcenter spring connecting said handle with said actuating element for moving said actuating element to manually open and close said contacts, said support member when released causing disengagement of said movable 1| member trom said actuating element and opening of said contacts.

MERRILL G. LEONARD. 

